libinput: the road to 1.0

[Peter Hutterer]

Just as a heads-up, here's a short summary on what the plan is for libinput.
There are three milestones that are somewhat independent of each other:
* API/ABI stability promise
* libinput 1.0
* tablet, buttonset and touchpad gesture support

I made vague promises (on private channels) that we'll have a stable API by
the end of February. At the moment it looks like 0.11 is that API, there may
be another change in the next week or so but right now it looks like we're
good. I'll probably remove libinput_device_has_button() with one last soname
bump to have a clean start so you may want to update that soon.
So summary: the stable API/ABI is nigh, and 0.12 will likely have the last
API changes (if any).

the timeline for libinput 1.0 is currently unclear but it's just a number
anyway once we have a stable API. I expect it to happen either around 0.13
or 0.14 though, once parts of the gesture code have been merged and
polished.

tablet support: won't be in 0.12 and probably not in 1.0 either. one reason
we're frantically trying to get it almost finished is so we see whether
adding tablets would require changes to the rest of the API (as opposed to
just additions). atm it looks like what is left are merely additions, so
we're good. either way, still needs more polishing.

buttonset support: like tablet support, but it's even less mature and we
don't quite know what the API will be yet. but again, it doesn't look like
we'll need to change the main API. definitely not 0.12 or 1.0.

gesture support: we'll merge much of the gesture handling without the public
API for 0.12 or 0.13. gestures may make 1.0, as an addition on top of the
current API. we'll see.

Cheers,
   Peter